Semiconductor device obtained by dividing semiconductor wafer by use of laser dicing technique and method of manufacturing the same

ABSTRACT

A semiconductor chip is formed by dividing a semiconductor wafer by use of the laser dicing technique. The semiconductor chip has a laser dicing region on the side surface thereof. A dummy wiring layer is formed along the laser dicing region on the surface layer of the laser dicing region. A laser beam is applied to the dummy wiring layer to divide the semiconductor wafer.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2003-006387, filed Jan.14, 2003, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to a semiconductor device and amanufacturing method thereof and more particularly to a laser dicingtechnique for applying a laser beam to divide a semiconductor wafer intodiscrete chips.

[0004] 2. Description of the Related Art

[0005] It is predicted that a microprocessor now used is required toprocess a further larger amount of information at high speed in future.So far, miniaturization of transistors determines the performance of themicroprocessor. However, in recent years, RC delay (R: Resistance, C:Capacitance) causes a problem and much importance is given not only tominiaturization of transistors but also to parasitic capacitance(capacitance between wirings arranged with an insulating materialdisposed therebetween) and resistance of wirings which connecttransistors to one another.

[0006] In order to suppress the RC delay, it becomes necessary to changea wiring material from Al to Cu and use a material with a smalldielectric constant instead of a silicon oxide film as an insulatingmaterial. However, the insulating film with the small dielectricconstant generally has a porous structure and since the low dielectricproperty is acquired by virtue of the structure, the mechanical strengthand adhesion strength thereof are extremely low in comparison with thoseof the silicon oxide film. Therefore, when a semiconductor wafer isdiced into discrete chips, layer-layer separation tends to occur if theinsulating film with the small dielectric constant is mechanically cut.Further, since the Cu wiring (or copper conductor) is formed of amaterial having relatively high viscosity, film separation tends tooccur if a normal blade dicing process is performed.

[0007] Therefore, much attention is paid to laser dicing instead of theconventional blade dicing. In the laser dicing, a laser beam with highenergy is applied to melt and cut a semiconductor wafer. Therefore, itis expected that the cutting property of the Cu wiring and insulatingfilm with the small dielectric constant can be significantly enhanced incomparison with the grinding method such as the conventional bladedicing.

[0008] As the laser dicing, the following two methods are considered.The laser dicing methods are described in Jpn. Pat. Appln. KOKAIPublication No. 2002-192367, for example. The first method is to apply alaser beam after focusing the laser beam on the uppermost layer by useof a lens (condenser lens) 11 as shown in FIG. 1 and melt and cut awafer 12 together with a circuit element layer 13. The second method isto set the focusing position of a laser beam on the internal portion ofthe wafer 12 to form a melt processing region 16 due to multiphotonabsorption as shown in FIG. 2 and then discretely divide the wafer 12 bystretching a dicing film 15.

[0009] Since the first method requires extremely large laser power whenthe thick wafer 12 is cut, larger damages will be applied to the waferin comparison with a case of the blade dicing method in some cases.Therefore, the first method is suitable for a process of cutting onlythe circuit element layer 13 on the surface layer by use of relativelylow laser energy, for example.

[0010] Since the second method is to divide the wafer 12 starting fromthe melt processing region 16, it can cope with the relatively thickwafer 12. However, since insulating films and wiring layers (orinterconnections) are arranged in a complex form in the wiring patternof the circuit element layer 13 on the surface layer, there occurs apossibility that unexpected destruction such as separation of theinsulating film and layer-layer separation of the wiring layers willoccur at the time of dividing. Particularly, there occurs a strongpossibility that insulating films with small dielectric constant whichare recently actively used will be destroyed at the time of dividingbecause of characteristics such as the low mechanical strength and lowadhesion strength thereof.

[0011] That is, in the laser dicing, the surface state of a finishedto-be-cut member is largely influenced. More specifically, if focusingand power adjustment are made on a region in which metal wiring layersare present and the wafer is cut, large damage is given to a region inwhich no metal wiring layers are present and film separation occurs inthe worst case. Particularly, when a plurality of transparent filmswhich permit the laser beam to pass therethrough are laminated on adicing line region, the damage becomes significant. On the other hand,if focusing and power adjustment are made on a region in which no metalwiring layers are present, there occurs a possibility that the metalwiring layer cannot be cut in some cases.

[0012] Therefore, when the laser dicing is performed, it is required tofinely adjust a laser dicing device according to the surface state of ato-be-cut member. However, since patterns of metal wiring layers such asalignment marks and test pads are arranged in a complicated form in thedicing line region of the actual semiconductor wafer, it is difficult toadjust and set the laser dicing device into an optimum state.

[0013] As described above, the conventional semiconductor device and themanufacturing method thereof have a problem that the surface state of afinished to-be-cut member is influenced when the laser dicing isperformed, the quality is lowered and the cutting property andmanufacturing yield are lowered.

BRIEF SUMMARY OF THE INVENTION

[0014] A semiconductor device according to an aspect of the presentinvention comprises a semiconductor chip having a laser dicing region ona side surface, and a dummy wiring layer formed along the laser dicingregion on a surface layer of the laser dicing region.

[0015] A semiconductor device according to another aspect of the presentinvention comprises a semiconductor chip having a laser dicing region ona side surface, and a laser absorption member formed along the laserdicing region on a surface layer of the laser dicing region.

[0016] A semiconductor device according to still another aspect of thepresent invention comprises a semiconductor chip having a laser dicingregion on a side surface, an element region formed in the semiconductorchip, bumps formed on the semiconductor chip for connection with theexterior, a barrier metal layer formed between the bumps and externalelectrodes of elements formed in the element region, and a barrier metallayer formed along the laser dicing region on a surface layer of thelaser dicing region on the side surface of the semiconductor chip.

[0017] A method of manufacturing a semiconductor device according toanother aspect of the present invention comprises applying a laser beamto a semiconductor wafer except an alignment mark and testing padsformed in each region between semiconductor chips of the semiconductorwafer, and dividing the semiconductor wafer into discrete semiconductorchips.

[0018] A method of manufacturing a semiconductor device according toanother aspect of the present invention comprises focusing a laser beamon a surface layer side of a dicing line region, applying a laser beamto a semiconductor wafer except an alignment mark and testing padsformed in each region between semiconductor chips to form a cut regionshallower than thickness of the semiconductor wafer, focusing a laserbeam on a deep layer side of the semiconductor wafer corresponding inposition to the cut region, applying a laser beam to the semiconductorwafer except the alignment mark and testing pads formed in each regionbetween the semiconductor chips to form a melt processing region due tomultiphoton absorption in the semiconductor wafer, and dividing thesemiconductor wafer into discrete semiconductor chips.

[0019] A method of manufacturing a semiconductor device according tostill another aspect of the present invention comprises applying a laserbeam focused on a surface layer side of a dicing line region to asemiconductor wafer except an alignment mark and testing pads formed ineach region between semiconductor chips of the semiconductor wafer andapplying a laser beam focused on an internal portion of thesemiconductor wafer to the semiconductor wafer except the alignment markand testing pads formed in each region between the semiconductor chipsof the semiconductor wafer to form a cut region on the surface layerside of the semiconductor wafer and a melt processing region due tomultiphoton absorption on the deep layer side of the semiconductorwafer, and dividing the semiconductor wafer into discrete semiconductorchips.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0020]FIG. 1 is a cross sectional view showing a laser dicing step of afirst method, for illustrating a conventional semiconductor device and amanufacturing method thereof;

[0021]FIG. 2 is a cross sectional view showing a laser dicing step of asecond method, for illustrating a conventional semiconductor device anda manufacturing method thereof;

[0022]FIG. 3 is an enlarged pattern plan view showing two chips formedclose to each other in a semiconductor wafer and a region between thetwo chips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a first embodiment of the present invention;

[0023]FIG. 4 is an enlarged pattern plan view showing two chips formedclose to each other in a semiconductor wafer and a region between thetwo chips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a second embodiment of the presentinvention;

[0024]FIG. 5 is an enlarged pattern plan view showing two chips formedclose to each other in a semiconductor wafer and a region between thetwo chips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a third embodiment of the present invention;

[0025]FIG. 6 is an enlarged pattern plan view showing two chips formedclose to each other in a semiconductor wafer and a region between thetwo chips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a fourth embodiment of the presentinvention;

[0026]FIG. 7 is an enlarged pattern plan view showing two chips formedclose to each other in a semiconductor wafer and a region between thetwo chips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a fifth embodiment of the present invention;

[0027]FIG. 8 is an enlarged pattern plan view showing two chips formedclose to each other in a semiconductor wafer and a region between thetwo chips, for illustrating a semiconductor device and a manufacturingmethod thereof according to a sixth embodiment of the present invention;

[0028]FIG. 9 is a cross sectional view showing a first step of laserdicing, for illustrating a semiconductor device and a manufacturingmethod thereof according to a seventh embodiment of the presentinvention;

[0029]FIG. 10 is a cross sectional view showing a second step of laserdicing, for illustrating the semiconductor device and the manufacturingmethod thereof according to the seventh embodiment of the presentinvention;

[0030]FIG. 11 is a cross sectional view showing a laser dicing step, forillustrating a semiconductor device and a manufacturing method thereofaccording to an eighth embodiment of the present invention; and

[0031]FIG. 12 is a cross sectional view showing a laser dicing step, forillustrating a semiconductor device and a manufacturing method thereofaccording to a ninth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0032] [First Embodiment]

[0033]FIG. 3 shows two chips (semiconductor chips) 21-1, 21-2 which areformed close to each other in a semiconductor wafer and a region 22between the chips 21-1 and 21-2 in an enlarged form, for illustrating asemiconductor device and a manufacturing method thereof according to afirst embodiment of the present invention. In a portion near the centralportion of the region 22, an alignment mark 24 and test pads 25-1, 25-2,25-3 are arranged. Further, laser dicing regions 23-1, 23-2 arestraightly arranged along the outer peripheries of the respective chips21-1, 21-2 to avoid the alignment mark 24 and test pads 25-1, 25-2,25-3. Wiring layers are respectively formed on the front surface layersof the laser dicing regions 23-1, 23-2. The wiring layers are not usedto make an electrical connection but used as dummy patterns (dummywiring layers) which make laser beam application regions uniform andpermit the laser beam to be easily absorbed. For example, the dummywiring layer is formed by using the same layer as metal wiring layersused in element regions of the chips 21-1, 21-2 together with thealignment mark 24 and test pads 25-1, 25-2, 25-3.

[0034] When the semiconductor wafer is divided into the discrete chips21-1, 21-2, a laser beam is applied onto the laser dicing regions (metalwiring layers) 23-1, 23-2 to melt and cut the laser dicing regions. Atthe time of melting and cutting, the focusing position of the laser beamis set on the uppermost layer by use of a lens and the laser beam isapplied to melt and cut the wafer.

[0035] Further, after the focusing position of the laser beam is set onthe internal portion of the wafer and the laser beam is applied to forma melt processing region due to multiphoton absorption, the wafer can bedivided into discrete chips by cracking or stretching a dicing film.

[0036] With the above configuration and manufacturing method, since themetal wiring layers are formed on the laser dicing regions 23-1, 23-2and the surface states thereof are uniform, the quality of the finishedproduct will not vary. Further, since the dummy wiring layer (metalwiring layer) tends to absorb the laser beam, the cutting property inthe laser dicing step can be improved. Of course, since the wafer isdivided by melting, there is no possibility that chippings occurring inthe dicing step in which a mechanical grinding process using a blade isperformed will occur. Further, focusing and power adjusting of the laserdicing device can be easily attained. In addition, since the alignmentmark 24, test pads 25-1, 25-2, 25-3 and dummy wiring layers are formedby use of the same layer as the metal wiring layers used in the elementregions in the chips 21-1, 21-2, it is only necessary to change thedesign of a mask used to form a pattern of the metal wiring layers ofthe element regions. Therefore, the manufacturing process will not becomplicated and the manufacturing cost will not rise.

[0037] When the metal wiring layers are not present under the laserdicing regions 23-1, 23-2, the same effect can be attained if straightmetal wiring layers are not forcibly arranged on the uppermost layers.

[0038] [Second Embodiment]

[0039]FIG. 4 shows two chips (semiconductor chips) 21-1, 21-2 which areformed close to each other in a semiconductor wafer and a region 22between the two chips 21-1 and 21-2 in an enlarged form, forillustrating a semiconductor device and a manufacturing method thereofaccording to a second embodiment of the present invention. On the chip21-1 side and the chip 21-2 side of the region 22, an alignment mark 24and test pads 25-1, 25-2, 25-3 are respectively arranged. Further, alaser dicing region 23 is straightly arranged in a portion near thecentral portion of the region 22 to avoid the alignment mark 24 and testpads 25-1, 25-2, 25-3. A wiring layer is formed on the front surfacelayer of the laser dicing region 23. The wiring layer is not used tomake an electrical connection but used as a dummy pattern (dummy wiringlayer) which makes a laser beam application region uniform and permitsthe laser beam to be easily absorbed. For example, the dummy wiringlayer is formed by using the same layer as metal wiring layers used inelement regions of the chips 21-1, 21-2 together with the alignment mark24 and test pads 25-1, 25-2, 25-3.

[0040] When the semiconductor wafer is divided into the discrete chips21-1, 21-2, a laser beam is applied onto the laser dicing region (metalwiring layer) 23 to melt and cut the laser dicing region. At the time ofmelting and cutting, the focusing position of the laser beam is set onthe uppermost layer by use of a lens and the laser beam is applied tomelt and cut the wafer. Further, after the focusing position of a laserbeam is set on the internal portion of the wafer and the laser beam isapplied to form a melt processing region due to multiphoton absorption,the wafer can be divided into discrete chips by cracking or stretching adicing film.

[0041] With the above configuration and manufacturing method, since thedummy wiring layer (metal wiring layer) is formed on the uppermost layerof the laser dicing region 23 and the surface state thereof is uniform,the quality of the finished product will not vary. Further, since themetal wiring layer tends to absorb the laser beam, the cutting propertyin the laser dicing step can be improved. Of course, since the wafer isdivided by melting, there is no possibility that chippings occurring inthe dicing step in which a mechanical grinding process using a blade isperformed will occur. Further, focusing and power adjusting of the laserdicing device can be easily attained. In addition, since the alignmentmark 24, test pads 25-1, 25-2, 25-3 and dummy wiring layer are formed byuse of the same layer as the metal wiring layers used in the elementregions in the chips 21-1, 21-2, it is only necessary to change thedesign of a mask used to form a pattern of the metal wiring layers ofthe element regions. Therefore, the manufacturing process will not becomplicated and the manufacturing cost will not rise.

[0042] When the metal wiring layer is not present under the laser dicingregion 23, the same effect can be attained if a straight metal wiringlayer is not forcibly arranged on the uppermost layer.

[0043] [Third Embodiment]

[0044]FIG. 5 shows two chips (semiconductor chips) 21-1, 21-2 which areformed close to each other in a semiconductor wafer and a region 22between the two chips 21-1 and 21-2 in an enlarged form, forillustrating a semiconductor device and a manufacturing method thereofaccording to a third embodiment of the present invention. In the thirdembodiment, in a case where it is difficult to shift an alignment mark24 or test pads 25-1 to 25-5, laser dicing regions (metal wiring layers)23-1, 23-2 are adequately bent and arranged to avoid the arranged markand pads.

[0045] A laser dicing device can freely move the application position ofa laser beam in XY directions. Therefore, when the semiconductor waferis divided into the discrete chips 21-1, 21-2, a laser beam is appliedonto the bent metal wiring layers to melt and cut the laser dicingregions. Further, after the focusing position of a laser beam is set onthe internal portion of the wafer and the laser beam is applied to forma melt processing region due to multiphoton absorption, the wafer can bedivided into discrete chips by cracking or stretching a dicing film.

[0046] With the above configuration and manufacturing method, since thedummy wiring layers (metal wiring layers) are formed on the laser dicingregions 23-1, 23-2 and the surface states thereof are uniform, thequality of the finished product will not vary. Further, since the metalwiring layer tends to absorb the laser beam, the cutting property in thelaser dicing step can be improved. Of course, since the wafer is dividedby melting, there is no possibility that chippings occurring in thedicing step in which a mechanical grinding process using a blade isperformed will occur. Further, focusing and power adjusting of the laserdicing device can be easily attained. In addition, since the alignmentmark 24, test pads 25-1 to 25-5 and dummy wiring layers are formed byuse of the same layer as the metal wiring layers used in the elementregions in the chips 21-1, 21-2, it is only necessary to change thedesign of a mask which is used to form a pattern of the metal wiringlayers of the element regions. Therefore, the manufacturing process willnot be complicated and the manufacturing cost will not rise.

[0047] When the metal wiring layers are not present under the laserdicing regions 23-1, 23-2, it is not necessary to forcibly arrange thebent wiring layers on the uppermost layers.

[0048] A case wherein the two dicing line regions are bent and arrangedis explained as an example, but it is of course possible to bend andarrange one dicing line region.

[0049] [Fourth Embodiment]

[0050]FIG. 6 shows two chips (semiconductor chips) 21-1, 21-2 which areformed close to each other in a semiconductor wafer and a region 22between the two chips 21-1 and 21-2 in an enlarged form, forillustrating a semiconductor device and a manufacturing method thereofaccording to a fourth embodiment of the present invention. In the fourthembodiment, a polyimide film (which is formed of a polyimide-seriesmaterial or is a laser beam absorbing film of the same kind) 26 isformed in a region 22.

[0051] Generally, in a semiconductor device with respect to which bladedicing is performed, the polyimide film on the region 22 is previouslyselectively removed in order to prevent generation of cutting chips andseparation of a surface protection film of polyimide formed on theelement region. However, in the fourth embodiment, the polyimide film 26formed on the element region is intentionally formed to extend over theregion 22.

[0052] With the above configuration and manufacturing method, thepolyimide film (formed of a polyimide material or a material of the samekind) is apparently observed non-uniform since the underlying layer istransparent. However, since it absorbs the laser beam, a cutting processcan be uniformly performed and the cutting property in the laser dicingstep can be improved. Further, since the polyimide film is formed byextending a film used as a surface protection film of the elementregion, the manufacturing process will not be complicated and themanufacturing cost will not rise.

[0053] In the above explanation, the polyimide film (which is formed ofa polyimide-series material or is a laser beam absorbing film of thesame kind) 26 is formed on the entire surface of the region 22 betweenthe chips 21-1 and 21-2. However, it is also possible to selectivelyarrange the film only on the laser application region, that is, laserdicing region 23.

[0054] [Fifth Embodiment]

[0055]FIG. 7 shows two chips (semiconductor chips) 21-1, 21-2 which areformed close to each other in a semiconductor wafer and a region 22between the two chips 21-1 and 21-2 in an enlarged form, forillustrating a semiconductor device and a manufacturing method thereofaccording to a fifth embodiment of the present invention. In the fifthembodiment, a sheet-like film (laser absorbing member) 27 which absorbsa laser beam is closely attached to and formed on the region 22.

[0056] Laser dicing is performed with respect to the semiconductor wafertogether with the above film.

[0057] With the above configuration and manufacturing method, basicallythe same operation and effect as those of the first to fourthembodiments can be attained.

[0058] It is possible to form an opening 28 in a position correspondingto an alignment mark 24 at the time of dicing, if necessary. Further,instead of the sheet-like film 27, a coating film or a film cured aftercoating a liquid-form material or a film electrochemically formed can beused. The above film or coating film can be selectively formed on theregion 22 or can be formed on the entire surface of the wafer if it isformed of a material which can be removed after the dicing process.

[0059] [Sixth Embodiment]

[0060]FIG. 8 shows two chips (semiconductor chips) 21-1, 21-2 which areformed close to each other in a semiconductor wafer and a region 22between the two chips 21-1 and 21-2 in an enlarged form, forillustrating a semiconductor device and a manufacturing method thereofaccording to a sixth embodiment of the present invention. In the sixthembodiment, for example, when bumps 28-1A, 28-1B, . . . , 28-2A, 28-2B,. . . are formed on external electrodes of semiconductor elements formedin the element regions of the chips 21-1, 21-2, barrier metal layersprovided between the bumps 28-1A, 28-1B, . . . , 28-2A, 28-2B, . . . andthe external electrodes of the semiconductor elements are arranged onlaser dicing regions 23-1, 23-2.

[0061] With the above configuration and manufacturing method, basicallythe same operation and effect as those of the first to fourthembodiments can be attained.

[0062] In FIG. 8, a case wherein the arrangement of the laser dicingregion is the same as that shown in FIG. 3 is explained as an example,but the arrangement as shown in FIG. 4 or 5 can be applied in the samemanner.

[0063] [Seventh Embodiment]

[0064]FIGS. 9 and 10 show a laser dicing step, for illustrating asemiconductor device and a manufacturing method thereof according to aseventh embodiment of the present invention. The laser dicing stepaccording to the seventh embodiment can be applied to any one of thelaser dicing steps in the first to sixth embodiments.

[0065] First, as shown in FIG. 9, the rear surface of a semiconductorwafer 32 is affixed to a dicing film 35 in order to make a cut in thefront surface layer of the wafer 32. Then, the focusing position of alaser beam is set on the uppermost layer (or on the front surface layerside) by use of a lens (condenser lens) 31 and the laser beam is appliedto a dicing region 33 on the element region side to make an extremelyshallow cut and thus form a cut region 34. The dicing region 33corresponds to one of the laser dicing regions 23-1, 23-2 and 23 in thefirst to sixth embodiments and the laser beam is applied to a portionother than the alignment mark and test pads.

[0066] After formation of the cut region 34, as shown in FIG. 10, thefocusing position of the laser beam is set on the internal portion (onthe deep layer side) of the wafer 32 and the laser beam is applied tothe wafer 32 from the rear surface side of the wafer 32 via the dicingfilm 35 to form a melt processing region 36 due to multiphotonabsorption along the cut region 34. Then, the wafer is discretelydivided.

[0067] Thus, by separately performing the laser dicing process twice forthe surface layer side and for the deep layer side, since laser powerwhen the cut region 34 is formed is used to make a cut only in thesurface layer portion and can be made relatively low, a cut by the laserbeam is small and a region required for dicing can be made relativelysmall. Further, since laser power used when the melt processing region36 is formed can also be made low, unexpected destruction such asseparation of the insulating film and layer-layer separation of thewiring layers occurring at the time of dividing can be suppressed.

[0068] When carrying out the laser dicing step twice for the surfacelayer side and for the deep layer side, it is possible to use two laserdicing devices or one laser dicing device which can be used for both ofthe steps.

[0069] [Eighth Embodiment]

[0070]FIG. 11 shows a laser dicing step, for illustrating asemiconductor device and a manufacturing method thereof according to aneighth embodiment of the present invention. In the eighth embodiment,the dicing process which is performed in two steps in the seventhembodiment is performed in one step. That is, the focusing position of alaser beam is set on the uppermost layer (front surface layer side) byuse of a lens (condenser lens) 31-1 and the laser beam is applied fromthe element forming surface side of a wafer 32, and at the same time,the focusing position of a laser beam is set on the internal portion(deep layer side) of the wafer 32 by use of a lens (condenser lens) 31-2and the laser beam is applied thereto from the rear surface side of thewafer 32 via a dicing film 35. Thus, a cut region 34 and melt processingregion 36 due to multiphoton absorption are formed substantially at thesame time and then the wafer is discretely divided.

[0071] With the above configuration and manufacturing method,substantially the same operation and effect as those of the seventhembodiment can be attained. Although metal wiring layers, polyimidefilms or laser absorption members are not formed on the rear surfaceside of the wafer 32, the quality of the finished product will not varysince no semiconductor elements are present on the rear surface side andthe surface state is uniform. Further, substantially no influence isgiven to the element region even if laser beam power is increased tosome extent.

[0072] [Ninth Embodiment]

[0073]FIG. 12 shows a laser dicing step, for illustrating asemiconductor device and a manufacturing method thereof according to aninth embodiment of the present invention. In the ninth embodiment, thedicing process which is performed in two steps in the seventh embodimentis performed in one step. That is, the focusing position of a laser beamis set on the uppermost layer (front surface layer side) by use of alens (condenser lens) 31-1 and the laser beam is applied from theelement forming surface side of a wafer 32, and at the same time, thefocusing position of a laser beam is set on the internal portion (deeplayer side) of the wafer 32 by use of a lens (condenser lens) 31-2 andthe laser beam is applied thereto. Thus, a cut region 34 and meltprocessing region 36 due to multiphoton absorption are formedsubstantially at the same time and then the wafer is discretely divided.

[0074] With the above configuration and manufacturing method,substantially the same operation and effect as those of the seventh andeighth embodiments can be attained.

[0075] In the seventh to ninth embodiments, a case wherein the wafer isdivided only by laser dicing is explained as an example, but the laserdicing process can be performed not to completely divide the wafer andthen the wafer 32 can be divided into discrete chips by cracking orstretching a dicing film 35.

[0076] Further, the laser dicing process is performed as trimming andthe wafer can be finally divided by normal blade dicing.

[0077] As described above, according to one aspect of this invention, asemiconductor device with high quality can be attained.

[0078] Further, a semiconductor device manufacturing method which canimprove the cutting property in the laser dicing step and themanufacturing yield can be attained.

[0079] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A semiconductor device comprising: asemiconductor chip having a laser dicing region on a side surface, and adummy wiring layer formed along the laser dicing region on a surfacelayer of the laser dicing region.
 2. The semiconductor device accordingto claim 1, wherein the dummy wiring layer is straightly formed along anouter periphery of the semiconductor chip.
 3. The semiconductor deviceaccording to claim 2, further comprising at least one of an alignmentmark and test pads provided between the outer periphery of thesemiconductor chip and the dummy wiring layer.
 4. The semiconductordevice according to claim 1, further comprising at least one of analignment mark and test pads provided between the outer periphery of thesemiconductor chip and the dummy wiring layer.
 5. The semiconductordevice according to claim 4, wherein the dummy wiring layer is formed ina bent form to avoid the alignment mark and test pads.
 6. Thesemiconductor device according to claim 1, wherein the dummy wiringlayer is formed of the same layer as a wiring layer in an elementregion.
 7. The semiconductor device according to claim 1, furthercomprising a cut region formed on a surface layer side of the laserdicing region by use of a laser beam and a melt processing region due tomultiphoton absorption formed on a deep layer side of the laser dicingregion corresponding in position to the cut region.
 8. A semiconductordevice comprising: a semiconductor chip having a laser dicing region ona side surface, and a laser absorption member formed along the laserdicing region on a surface layer of the laser dicing region.
 9. Thesemiconductor device according to claim 8, wherein the laser absorptionmember is formed in a sheet form and has an opening in a positioncorresponding to an alignment mark.
 10. The semiconductor deviceaccording to claim 8, wherein the laser absorption member is a surfaceprotection film formed on an element region of the semiconductor chip.11. The semiconductor device according to claim 10, wherein the surfaceprotection film is formed to extend from the element region of thesemiconductor chip over to the laser dicing region.
 12. Thesemiconductor device according to claim 10, wherein the surfaceprotection film is formed of a polyimide-series material.
 13. Thesemiconductor device according to claim 8, further comprising at leastone of an alignment mark and test pads provided between the outerperiphery of the element region in the semiconductor chip and the laserdicing region.
 14. The semiconductor device according to claim 8,further comprising a cut region formed on a surface layer side of thelaser dicing region by use of a laser beam and a melt processing regiondue to multiphoton absorption formed on a deep layer side of the laserdicing region corresponding in position to the cut region.
 15. Asemiconductor device comprising: a semiconductor chip having a laserdicing region on a side surface, an element region formed in thesemiconductor chip, bumps formed on the semiconductor chip forconnection with the exterior, a barrier metal layer formed between thebumps and external electrodes of elements formed in the element region,and a barrier metal layer formed along the laser dicing region on asurface layer of the laser dicing region on the side surface of thesemiconductor chip.
 16. The semiconductor device according to claim 15,further comprising at least one of an alignment mark and test padsprovided between the outer periphery of the element region in thesemiconductor chip and the laser dicing region.
 17. The semiconductordevice according to claim 15, further comprising a cut region formed ona surface layer side of the laser dicing region by use of a laser beamand a melt processing region due to multiphoton absorption formed on adeep layer side of the laser dicing region corresponding in position tothe cut region.
 18. A method of manufacturing a semiconductor devicecomprising: applying a laser beam to a semiconductor wafer except analignment mark and testing pads formed in each region betweensemiconductor chips of the semiconductor wafer, and dividing thesemiconductor wafer into discrete semiconductor chips.
 19. A method ofmanufacturing a semiconductor device comprising: focusing a laser beamon a front surface layer side of a dicing line region, applying a laserbeam to a semiconductor wafer except an alignment mark and testing padsformed in each region between semiconductor chips to form a cut regionshallower than thickness of the semiconductor wafer, focusing a laserbeam on a deep layer side of the semiconductor wafer corresponding inposition to the cut region, applying a laser beam to the semiconductorwafer except the alignment mark and testing pads formed in each regionbetween the semiconductor chips to form a melt processing region due tomultiphoton absorption in the semiconductor wafer, and dividing thesemiconductor wafer into discrete semiconductor chips.
 20. Thesemiconductor device manufacturing method according to claim 19, whereinforming the melt processing region is to apply the laser beam from arear surface side of the semiconductor wafer via a dicing film.
 21. Thesemiconductor device manufacturing method according to claim 19, whereinforming the melt processing region is to apply the laser beam from anelement region side of the semiconductor wafer.
 22. The semiconductordevice manufacturing method according to claim 19, wherein the laserbeam is applied to the region between the semiconductor chips in astraight form.
 23. The semiconductor device manufacturing methodaccording to claim 19, wherein the laser beam is applied to the regionbetween the semiconductor chips in a bent form.
 24. A method ofmanufacturing a semiconductor device comprising: applying a laser beamfocused on a front surface layer side of a dicing line region to asemiconductor wafer except an alignment mark and testing pads formed ineach region between semiconductor chips of the semiconductor wafer andapplying a laser beam focused on an internal portion of thesemiconductor wafer to the semiconductor wafer except the alignment markand testing pads formed in each region between the semiconductor chipsof the semiconductor wafer to form a cut region on the front surfacelayer side of the semiconductor wafer and a melt processing region dueto multiphoton absorption on the deep layer side of the semiconductorwafer, and dividing the semiconductor wafer into discrete semiconductorchips.
 25. The semiconductor device manufacturing method according toclaim 24, wherein the laser beam is applied to the region between thesemiconductor chips in a straight form.
 26. The semiconductor devicemanufacturing method according to claim 24, wherein the laser beam isapplied to the region between the semiconductor chips in a bent form.